be quiet! Pure Power 12 M 850W
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be quiet! Pure Power 12 M 850W review
Researched, not hands-on tested.How we review ›
by SudoPicks Research · editor Paul HR · published 25 Oct 2026 · updated 25 Oct 2026
This is an 850 W fully modular ATX 3.0 power supply for builders who want a quiet PC with a modern GPU connector. It suits gaming and general-purpose desktops that will rarely sit near full load.
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New to power supplies? What they are and what to look for
The power supply (PSU) turns mains electricity into the power every part of a desktop PC runs on. A good one is quiet, efficient and protects the rest of the PC if something goes wrong.
Do you need a power supply? Every desktop build needs one. Pre-built PCs already have one, but upgrading to a bigger graphics card can mean a bigger power supply.
What to look for
- Enough watts for your graphics card and processor, with some to spare: our PC build planner works it out
- 80 Plus Gold or better for lower running costs
- A long warranty: 7 to 10 years signals a well-made unit
Unsure about a word? Jargon explained
How the 7.7 adds up
Our power supplies rubric- Quality and protections30% of score
- Efficiency20% of score
- Noise15% of score
- Cabling and connectors20% of score
- Warranty15% of score
Against the 16 power supplies we've reviewed
bar = the range of all 16 · dot = this one · better →
- Overall score 7.7/10joint 1st of 16
Support and features
| Software updates | No end-of-support or end-of-life date announced; the search was limited, so this is unverified. |
|---|
Pros and cons
+ pros
- Fully modular with a native 12VHPWR cable
- 10-year warranty
- Quiet up to mid load, with low ripple
− cons
- No zero-fan mode; fan spins at low load
- Fan noise climbs above 35 dBA past 740 W
- 73.8% efficiency at 2% load (230V)
Price history
Price history appears here once we have tracked this product for a few days.
The full review
Where it fits
The Pure Power 12 M 850W is an ATX 3.0, PCIe 5.1 compatible unit rated at 850 W continuous and 900 W peak. It is fully modular and carries an 80 PLUS Gold rating. be quiet! gives it a 10-year warranty. The platform maker is HEC.
That combination suits a mainstream or high-end gaming build. It also suits a workstation that needs headroom for a current graphics card. Hardware Busters describes its street price as in line with competitors, and owners praise it as reasonable value.
Build quality and protections7/10
The manufacturer cites an LLC topology for voltage regulation. Independent numbers back up the electrical side. Guru3d recorded a worst-case 12V ripple of 21 mV peak to peak at 100% load. Hardware Busters measured 12V ripple up to 23.5 mV at 100% load. The two reviews land close together.
Be quiet! lists a full set of protections: OTP, OCP, OPP, SCP, OVP, UVP and SIP. That covers the standard over-current, over-voltage and short-circuit cases, plus over-temperature and over-power. With an HEC platform, two ripple tests and that protection list, the quality case is solid.
Efficiency7/10
The unit is 80 PLUS Gold. The manufacturer quotes up to 93.2%. Cybenetics gives it a Platinum rating at 115V, with efficiency of 89 to 91%.
The manufacturer's 230V figures show how the curve behaves. Efficiency is 87.1% at 10% load, 91.7% at 20%, 93.2% at 50% and 91.2% at 100%. It is weakest at the very bottom, at 73.8% at 2% load. A PC that idles most of the day will spend time in that region, so the always-on case is the least flattering one for this unit. Under normal desktop and gaming loads the curve is strong.
Noise7/10
The fan is a single 120 mm rifle bearing model that tops out at 2000 rpm. There is no zero-fan mode. The fan keeps spinning at low load, and some owners wanted a 0 rpm option. Owners still praise quiet operation overall.
The manufacturer's figures support that praise. It lists 9.3 dB(A) at 10% load, 9.4 at 20% and 9.5 at 50%. At 100% load the figure rises to 25.7 dB(A). Hardware Busters measured fan noise of 20 to 25 dBA between about 470 W and 580 W. Above 740 W it passed 35 dBA. A build that draws well under 740 W should stay in the quiet range. A system that regularly pulls close to the 850 W limit will hear the fan work.
Cabling and connectors8/10
The unit has one native 12VHPWR connector rated at 600 W. The 12V output is 850 W combined, and the 12VHPWR output is capped at 600 W combined. That gives a modern high-power graphics card a direct cable without an adapter.
For older or multi-cable setups there are four PCIe 6+2-pin connectors. CPU power comes from one P8 and one P4+4. Storage gets six SATA connectors and two PATA connectors. Full modularity means a small case only needs the cables it uses.
Warranty10/10
The unit carries a 10-year warranty. The cover runs alongside ATX 3.0 and 12VHPWR support, so the warranty period and the modern connector set come together in one unit.
Who it suits
It suits builders who want modern connectors, tight 12V ripple and low noise at everyday loads. The fan behaviour is the main trade-off. Silent-PC builders who want the fan to stop at idle should look elsewhere. Anyone planning sustained loads above 740 W should account for the fan noise Hardware Busters measured there.
What owners report
Recurring themes from public owner feedback, summarised in our own words.
- Owners praise the quiet operation.
- Some owners dislike that the fan spins at low load and want a 0 rpm mode.
- Owners describe it as reasonable value.
Who should skip it
- Silent-PC builders who want the fan to stop at idle
- Buyers planning sustained loads close to 850 W who need low noise
- Builders needing more than six SATA connectors
Full specifications
| Rated output (W) | 850 W continuous, 900 W peak; 850 W combined 12V output, 600 W combined 12VHPWR |
|---|---|
| Efficiency rating (80 Plus or Cybenetics) | 80 PLUS Gold; up to 93.2% (manufacturer); Cybenetics [115V] Platinum rating, 89–91% |
| Form factor (ATX or SFX) and ATX 3.x / PCIe 5.x support | ATX 3.0; PCIe 5.1 compatible |
| Modular cabling (fully, semi or non-modular) | Fully modular |
| Graphics card connectors (12V-2x6 / 12VHPWR and PCIe 8-pin count) | One 12VHPWR (600 W); four PCIe 6+2-pin; one P8 and one P4+4 CPU; six SATA; two PATA |
| Fan size and zero-fan mode | One 120 mm rifle bearing fan, max 2000 rpm; no zero-fan mode |
| Warranty (years) | 10 years |
Alternatives
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